Coal digger



E. STEPHENSON Aug. 14, 1951 GOAL DIGGER 3 Sheets-Sheet l INVEN TOR. E014/020 $rPHws0m Filed June 17, 1949 Aug. 14, 1951 E STEPHENSON COALDIGGER Filed June 17, 1949 3 Sheets-Sheet 2 Aug. 14, 1951 E. STEPHENSONCOAL DIGGER 3 Sheets-Sheet 5 Filed June 17, 1949 ATIE INVENTOR. fan 4 90SrEPHEmM/Y Patented Aug. 14, 1951 UNITED s'rsrss rarer EFlC COAL BIGGEREdward Stephenson, Carrier Mills, Ill.

Application June 17, 1949, Serial No. 99,798

Claims. 1

This invention relates to coal-digging machines, and more particularlyto a machine adapted to dig coal off a solid mass in a mine and load itinto a bin for discharge into a shuttle car or other conveyance.

A main object of the invention is to provide a novel and improvedcoal-digging machine which is relatively simple in construction, easy tooperate, and which digs coal off a solid mass and loads it into astorage bin ready to be discharged into a shuttle car or otherconveyance for moving the coal from the working face to the tipple.

A further object of the invention is to provide an improved coal-diggingmachine which is sturdy in construction, substantially automatic inoperation, and which renders unnecessary many operations formerlyrequired in coal mining, such as undercutting, drilling, blasting andmanual loading.

A still further object of the invention is to provide an improvedcoal-digging machine which eliminates many of the hazards encountered inpresent methods of mining, said machine involving relatively few parts,being easy to maintain in operation, and having a high capacity wherebya great saving in time and labor is provided in mining coal by the useof the machine.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

Figure 1 is a side elevational view of a coalmining machine constructedin accordance with the present invention shown in an initial operatingposition thereof;

Figure 2 is a view similar to Figure 1, but showing the machine in asecond position of operation thereof;

Figure 3 is a View similar to Figure .1, but showing the machine in athird position of operation thereof;

Figure 4 is a top plan view of the machine of Figure l; s

Figure 5 is a rear elevational view of the machine of Figure 1;

Figure 6 is a front elevational view of the machine of Figure 1;

Figure 7 is a vertical longitudinal cross-sectional view of the machineof Figure 1;

Figure 8 is an enlarged fragmentary crosssectional detail view taken online 8-8' of Figure 6;

Figure 9 is an enlarged cross-sectional detail view taken on line 9-9 ofFigure 4;

Figure 10 is a top plan detail view of the cut 2 ting head of themachine of Figure 1, with the conveyor chain removed;

Figure 11 is a cross-sectional detail view taken on line HII of Figure9.

Referring to the drawings, the coal-digging machine is designatedgenerally at H. Said machine comprises an elongated bin portion I2 tothe forward end of which is pivotally connected the digging head 39.

The bin portion [2 has vertical side walls l3, a bottom wall It, a frontwall l5, an upwardlyand rearwardly-inclined rear wall It, and ahoriaontal extension of said rear wall, shown at ll, which defines withside walls l3, [3 a discharge chute at the rear of the bin portion [2.As shown in Figure '7, the bin portion l 2 is provided with an endlesschain conveyor l8, extending along bottom wall 14, inclined rear wallIt, and the discharge chute bottom wall l1, said conveyor extendingsubstantially the full width of the bin portion l2 and being driven byan electric motor l9 secured to the rear portion of one of the sidewalls I3, and whose shaft is coupled, as by a belt 25], to a transversesprocket shaft 2| journaled in the rear end portions of the side Wallsand having suitable sprockets engaging the side links of the chainconveyor Ill. The chain conveyor I8 is provided withoutwardly-projecting spaced lugs 22 acting to propel material depositedon the chain conveyor rearwardly out of the bin portion l 2 as the chainconveyor is driven by the motor IS, The chain conveyor is supported onrespective sprocket shafts 23 and 24 adjacent the upper and lower endsof the inclined rear wall l6, and on a sprocket shaft 25 adjacent thefront wall l5, said sprocket shafts being journaled in the side wallsI3, l3. The motor is is automatically controlled by a push button switch26 mounted on the upper portion of front wall l5 adjacent the forwardend of chain conveyor I8. Hinged to front wall l5 at a point above theswitch 26 is a plate member 21 overlying the actuating button of theswitch. The plate member 2'! is forced into abutment with the switchbutton by the lateral pressure of material accumulating on the forwardend of the chain conveyor. The switch is connected in the motorenergizing circuit. When the switch is closed, the motor I9 becomesenergized, starting the conveyor and moving the material rear- Wardlythereon. The switch opensas soon as the lateral pressure on hinged platemember 27 is removed, terminating operation of the conveyor.

Secured transversely in the bin 12 adjacent sprocket shaft 24 betweenthe upper and lower 3 elements of conveyor chain l8 and extendingthrough the side walls 13 is a shaft 28. Journaled on shaft 28 outwardlyadjacent the respective side walls [3 are driving wheels 29. Eachdriving wheel 29 is driven by an individual electric motor 30 mounted onthe side wall l3 adjacent thereto. Secured to the forward portion ofeach side wall I3 is an angle bracket 3|. Pivoted to the bracket 3| is adepending fluid pressure cylinder 32. Telescoped in each cylinder 32 isa piston sleeve 33 and provided in each sleeve 33 is a piston carried ona piston rod 34. Secured to the end of each piston rod 34 is a yoke 35carrying a Wheel 36 rotatably mounted between its arms. A caterpillartread belt 31 extends over each set of wheels 29 and 36 at therespective sides of the bin member l2. When fluid under pressure isintroduced into the cylinders 32, the forward end of the bin member I2is elevated from its normal position, shown in Figure 1, to a raisedposition, such as shown in Figures 2 and 3, due to the extension of thepiston sleeves 33 and piston rods 34. The machine may be movedlongitudinally by simultaneous energization of the motors 38, causingthe caterpillar belts 31 to be simultaneously driven. To turn themachine in one direc-- tion or the other, one of the motors 30 isenergized while the other motor 30 is de-energized.

Rotatably mounted in the upper forward corner portions of the side wallsl3, 13 above the forward wall I is a transverse shaft 38 carrying thedigging head 39. Said digging head comprises a pair of side wall members40, 4!], each side wall member comprising an intermediate plate element4| to opposite surfaces of which are secured outer plate elements 42, 42slightly larger in size than the intermediate plate element, therebydefining a peripheral guide groove extending around the peripheral edgeof the side wall member. Movably positioned in the peripheral guidegrooves thus defined are the respective chain cutters 43, 43. Thetransverse shaft 38 extends rotatably through the side wall elements 40at the rear end of the digging head. Rotatably secured to the forwardends of the side wall elements 40 is a transverse shaft 44 provided witha plurality of spaced abrading lugs 45. Rotatably secured to the uppermarginal portions of the wall members 40 rearwardly adjacent shaft 44 isanother transverse shaft 46 provided with similar abrading lugs. Securedon the shafts 38, 46 and 44 in recesses formed in the wall members 48are respective sprockets 47, 48 and 49 engaging the cutter chains 43, asshown in Figure 9.

At its intermediate portion, shaft 38 carries additional sprockets,shown at 56. Pivotally mounted on said shaft is a flat transversehousing 5|. Telescoped over housing 5| is another housing member 52having an end portion 53 in which is iournaled a transverse shaft 54.Shaft 54 carries sprockets 55 which are respectively longitudinallyaligned with the sprockets 50. Engaged over each set oflongitudinally-aligned sprockets 50 and 55 is a conveyor chain element56 having spaced lugs 66 thereon. Secured in housing elemerit 5| is alongitudinally-extending fluid pressure cylinder 51. Secured to the endportion 53 of housing element 52 is a piston rod 58 carried by a pistonslidably positioned in cylinder 51. Engaging the lower portion of eachchain element 56 is an idler wheel 59, the idler wheels being rotatablymounted on a common transverse shaft 60. The shaft 60 is connected byrespective link arms 6| and 62 to the respective housing elements 5|.and 52. By introducing fluid under pressure into the cylinder 51, thepiston rod 58 may be forced outwardly, increasing the effective lengthof the conveyor chains, 56, as compared with the normal effective lengththereof shown in Figure 8.

Secured to one of the side walls 13 of bin member 12 is an electricmotor 63 coupled, as by a belt 64, to a pulley 65 secured on shaft 38.When motor 63 is energized, shaft 38 is rotated, causing the cutterchains 43 to be moved in a counterclockwise direction, as viewed inFigures 8 and 9, and simultaneously causing the conveyor chains 56 to bemoved in a similar direction. The toothed shafts 44 and 46 are rotatedcounterclockwise at the same time, because of the counterclockwisemovement of sprockets 49 and 48 produced by the movement of chains 43.

Pivoted to each of the side walls l 3 of bin member I2 is a fluidpressure cylinder 6'! containing a piston provided with a piston rodshown at 68. The end of each piston rod 68 is pivotally connected at 69to a generally triangular plate member 10 secured to the adjacent sidewall member 40 of digging head 39. When fluid under pressure isintroduced into cylinders 67, the digging head is elevated from itsnormal position with respect to bin member 12, shown in Figures 1 and 2,to an elevated position with respect to said bin member, as shown, forexample, in Figure 3.

Designated at H is a source of fluid pressure, for example, amotor-driven pump, mounted on one of the side walls l3 of the bin memberl2. Mounted on said side wall I3 is a control valve 12 connected to pumpII by a conduit 13 and having respective outlet conduits l4 and 15. Theoutlet conduits 14 are connected to the respective bin-elevatingcylinders 32, 32. Valve '12 has a first control lever 16 which controlsthe admission of fluid under pressure into the conduits 14, '74. Theoutlet conduit 15 is connected to the respective cylinders 61 and 51.Valve 12 has a second control lever 11 which controls the admission offluid under pressure into the conduit 15. I

In operation, the machine, arranged in the position of Figure 1, isadvanced to engage the digging head 39 with the coal face, by means ofthe tread driving motors 30. The main drive motor 63 is then energizedto start the movement of the chain cutters 43, the toothed shafts 44 and46, and the conveyor chains 56. With the digging head elements runningand the head located at the proper place at the coal face, the motors 30are then energized to advance the digger head several feet into the coalface. Since the chain cutters 43 extend forwardly of the toothed shaft44, the coal face is sheared vertically, forming two vertical groovesadjacent the portion of the face engaged by the toothed shaft 44. Thetoothed shaft 44 cuts the coal between said grooves forwardly from thebottom of the face while the other rotary cutter shaft 46 splits theface, defining a block of coal. Meanwhile, the conveyor chains 56 arerunning. Due to the angle of attack defined b cutter shafts 44 and 46, aconsiderable amount of coal is loosened and thrown back onto theconveyor chains 56. The conveyor chains 56 move all the coal fallingthereon rearwardly over wall l5 into the bin member I2.'When'asubstantial amount of coal accumulates in said bin member, thechain conveyor [8 is actuated .by the closure of switch 26, as abovedescribed, moving the coal rearwardly out of the bin member into asuitable conveyance for hauling the coal to the surface of the mine.

When the digging head, in the position of Figure 1, is completely buriedin the coal face, the operator manipulates valve lever 76, admittingfluid under pressure to the jack cylinders 32, thereby elevating theforward end of the bin member [2 to the position of Figure 2. Thedigging head 39 meanwhile continues its cutting action but in an upwarddirection. The chain cutters 43 shear the coal vertically while thecutte shafts M and it out upwardly into the coal face, loosening thecoal and throwing same onto the conveyor chains 58 for rearward movementinto the bin member [2.

By manipulating valve lever 'l'l, fluid under pressure may be admittedinto cylinders 61 and '51, applying further upward force to the diggerhead and at the same time extending the conveyor chains 56. When thehead rises a few inches from the fire clay at the bottom of the face,the conveyor chains 56 become extended to their full length, reaching tothe back of the cut made by the front rotary toothed shaft 45. By beingthus extended, the conveyor chains 56 are in positions to catch all thecoal cut with a minimum of spillage. As the digging head is raised, itcuts and shears several inch s ahead of the lugs on the conveyor chainsas, making it easy for said lugs to pull the coal down.

When the roof of th cut is reached, the chine is arranged in theposition shown in Figure 3. The operator backs the machine by reversingthe motors 3G. The cutting elements on the digger head 39 continue toout until. they are clear of the coal.

When one out, such as described above, been made, the operator moves themachine laterally over the width of the cut and repeats the process.

It will be noted that the action of the rotary cutter shafts M and 46 isto cut out a block of coal by forward movement of the machine. When thedigger head 39 is elevated, the first block. is disintegrated into lumpsand has been largely conveyed rearwardl into the bin member [2 by theaction of the lugs on the conveyor chains 56. The upward movement of thecutter shafts M and .6 cuts out a second block of coal. This block isalso disintegrated by the action of the lugs on the extended conveyorchains 56.

While a specific embodiment of a coal-digging machine has been disclosedin the foregoing description, various modifications within the spirit ofthe invention may occur to those skilled in the art. Therefore, it isintended that no limitations be placed on the invention except asdefined by the scope of the appended claims.

What is claimed is:

1. In a coal digging machine, a bin, an endless belt conveyor positionedlongitudinally within said bin and rotatably supported therein, motivemeans operatively connected to said belt conveyor for effecting themovement thereof, ground engaging means carried by said bin andengageable with a ground surface for effecting the movement of said binalong said ground surface and for selectively elevating the forward endof said bin with respect to said ground surface, a digging headpositioned contiguous to said forward end of the bin and mounted on thelatter for movement toward and away from said ground surface, saiddigging head comprising a pair of spaced side walls, an endless chaincutter circumposed about each of said side walls and supported thereonfor movement thereabout, a first toothed shaft disposed transverselybetween said side walls contiguous to and spaced inwardly of the forwardends of said chain cutters and rotatabl supported on said side walls asecond toothed shaft disposed rearwardly of and spaced above said firsttoothed shaft androtatably supported on said side walls transverselythereof, conveyor means extending from subjacent said toothed shaftsrearwardly to said bin and movably supported on said side walls, meansfor simultaneously driving said chain cutters, toothed shafts and lastnamed conveyor means, and means connected between said bin and saiddigging head for effecting the movement of the latter with respect tosaid ground surface.

2. In a coal digging machine, a bin, an endless belt conveyor positionedlongitudinally within bin and rotatably supported therein, motive meansopera-tively connected to said belt conveyor for effecting the movementthereof, ground engaging means carried by said bin and engageable with aground surface for effecting the movement of said bin along said groundsurface and for selectively elevating the forward end of said bin withrespect to'said ground surface, a digging head positioned contiguous tosaid forward end of the bin and mounted on the latter for movementtoward and away from said ground surface, said digging head comprising apair of spaced side walls, an endless chain cutter circumposed abouteach of said side walls and supported thereon for movement thereabout, atoothed shaft disposed transversely between said side walls contiguousto and spaced inwardly of the forward ends of said chain cutters androta-tably supported on said side walls, a second toothed shaft disposedrearwardly of and spaced above said first toothed shaft and rotatablysupported on said side walls transversely thereof, conveyor deansextending from subjacent said toothed shafts rearwardly to said bin andmovably supported on said side walls, means for simultaneously drivingsaid chain cutters, toothed shafts and last named conveyor means, andmeans connected between said bin and said digging head for effecting themovement of the latter with respect to said ground surface, said groundengaging means comp-rising a first pair of wheels arranged on oppositesides of saidbin contiguous to the other end thereof and supportedthereon for rotary movement about a horizontal axis, a second pair ofwheels arranged contiguous to said forward end of said bin and in spacedaligned relation with respect to said first pair of wheels, ahydraulically actuated extensible arm connected to said bin and one ofthe wheels of said second pair and rotatably supporting the latter, anendless tread looped about the aligned wheels of said first and secondpairs and supported thereon, and means for introducing fluid underpressure into each of said extensible arms for selectively varying thelength of each of said arms.

3. In a coal digging machine, a bin, an endless belt conveyor positionedlongitudinally within said bin and rotatably supported therein, motivemeans operatively connected to said belt con veyor for effecting themovement thereof, ground engaging means carried by said bin andengageable with a ground surface for effecting the movement of said binalong said ground surface and for selectively elevating the forward endof said bin with respect to said ground surface, a digging headpositioned contiguous to said forward end of said bin and mounted on thelatter for movement toward and away from said ground surface, saiddigging head comprising a pair of spaced side walls, an endless chaincutter circumposed about each of said side walls and supported thereonfor movement thereabout, a first toothed shaft disposed transverselybetween said side walls contiguous to and spaced inwardly of the forwardends of said chain cutters and rotatably supported on said side walls, asecond toothed shaft disposed rearwardly of and spaced above said firsttoothed shaft and rotatably supported on said side walls transverselythereof, conveyor means extending from subjacent said toothed shaftsrearwardly to said bin and movably supported on said side walls, meansfor simultaneously driving said chain cutters, toothed shafts and lastnamed conveyor means, means connected between said bin and said digginghead for effecting the movement of the latter with respect to saidground surface, and pressure responsive switch means carried contiguousto one end of said bin and connected to said motive means for actuatingthe latter in response to the accumulation of material in said bin.

4. In a coal digging machine, a bin, an endless belt conveyor positionedlongitudinally within said bin and rotatably supported therein, motivemeans operatively connected to said belt conveyor for effecting themovement thereof, ground engaging means carried by said bin andengageable with a ground surface for effecting the movement of said binalong said ground surface and for selectively elevating the forward endof said bin with respect to said ground surface, a digging headpositioned contiguous to said forward end of the bin and mounted on thelatter for movement toward and away from said ground surface, saiddigging head comprising a pair of spaced side walls, an endless chaincutter circumposed about each of said side walls and supported thereonfor movement thereabout, a first toothed shaft disposed transverselybetween said side walls contiguous to and spaced inwardly of the forwardends of said chain cutters and rotatably supported on said side walls, asecond toothed shaft disposed rearwardly of and spaced above said firsttoothed shaft and rotatably supported on said side walls transverselythereof, conveyor means extending from subjacent said toothed shaftsrearwardly to said bin and movablysupported on said side walls, meansfor simultaneously driving said chain cutters, toothed shafts and lastnamed conveyor means, means connected between said bin and said digginghead for effecting the movement of the latter with respect to saidground surface, said last named conveyor means including a plurality 'ofconveyor chain elements disposed in side by side spaced relation withrespect to each other and mounted for movement about spaced horizontalaxes, and means connected between said horizontal axes for selectivelyvarying the spacing of said axes with respect to each other to therebyeffectively increase or decrease the length of each of said conveyorchain elements.

5. In a coal digging machine, a bin, an endless belt conveyor positionedlongitudinally within said bin and rotatably supported therein, motivemeans operatively connected to said belt conveyor for effecting themovement thereof, ground engaging means carried by said bin andengageable with a ground surface for effecting the movement of said binalong said ground surface and for selectively elevating the forward endof said bin with respect to said ground surface, a digging headpositioned contiguous to said forward end of the bin and mounted on thelatter for movement toward and away from said ground surface, saiddigging head comprising a pair of spaced side walls, an endless chaincutter circumposed about each of said side walls and supported thereonfor movement thereabout, a first toothed shaft disposed transverselybetween said side walls contiguous to and spaced inwardly of the forwardends of said chain cutters and rotatably supported on said side walls, asecond toothed shaft disposed rearwardly of and spaced above said firsttoothed shaft and rotatably supported on said side walls transverselythereof, conveyor means extending from subjacent said toothed shaftsrearwardly to said bin and movably supported on said side walls, meansfor simultaneously driving said chain cutters, toothed shafts and lastnamed conveyor means, means connected between said bin and said digginghead for effecting the movement of the latter with respect to saidground surface, said last named conveyor means including a lurality ofconveyor chain elements disposed in side by side spaced relation withrespect to each other and mounted for movement about spaced horizontalaxes, and means connected between said horizontal axes for selectivelyvarying the spacing of said axes with respect to each other to therebyeffectively increase or decrease the length of each of said conveyorchain elements, and idler means engaging each of said chain elements andconnected to said last named means for maintaining said chain elementstaut in all positions of said spaced axes.

EDWARD STEPHENSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date France Feb. 22, 1932Number Number

